Method and apparatus for setting moisture-setting printing inks



Oct. 14, 1952 c [RETON 2,613,603

METHOD AND APPARATUS FOR SETTING MOISTURE-SETTING PRINTING INKS FiledJune 11, 1947 IN VEN TOR.

ATTORNEYS 5o 45 BY Patented Oct. 14, 1952 METHOD AND APPARATUS FORSETTING MOISTURE-SETTING PRINTING INKS.

Carl A. Ireton, Dayton, Ohio, assignor to The Specialty Papers Company,Dayton, Ohio, a

corporation of Ohio Application June 11, 1947, Serial No. 753,917

8 Claims.

This invention relates to printing and is concerned particularly withthe setting of moisture-. setting inks which have been printed on paper.

It is a principal object of the invention to provide economical andefficient methods of setting moisture-setting inks by supplying moisturethereto in the form of steam under predetermined controlled conditionssuch that an amount of moisture suflicient to set the ink is impartedthereto in a highly uniform manner and without undesirably affecting thecharacter or properties of the paper itself.

It is a further object of the invention to provide such methods in whichsteam as available in a too wet state, unsuitable for uniform anddesirable effects upon direct application to the printed paper web, isfirst conditioned to a drier state of substantial freedom fromobjectionable large droplets of water and then is released, as from aconduit or chamber, in effective spaced relationship with respect to theweb and directed against the web with such velocity that the effectsaccompanying release of the steam and contact thereof with the cooleratmosphere and web material coupled with the energy lost in scrubbingagainst the web will cause the steam to be in a suitable state ofwetness or effective moisture content correlated with the hygroscopicpower of the ink solvent so as to favor rapid and uniform transfer ofmoisture from the steam to the ink in finely dispersed form.

It is also an object of the invention to provide improved apparatus forprinting in accordance with the moisture-setting principle andparticularly for effecting more satisfactory and more uniform setting ofthe moisture-setting inks on the paper without damaging the paperitself.

Another object of the invention is to provide simple, economical anddependable apparatus for setting moisture-setting inks which have beenprinted on paper by applying steam to the printed paper under controlledconditions uniformly across the web such as to cause the steam as itreaches the ink to be free of large droplets of water and yet beavailable for use in finely dispersed fog form upon reaching thevicinity of the paper and coming into contact with the ink printed onthe web itself.

Another object of the invention is to provide simple and effectiveapparatus for releasing steam in the vicinity of material to be treatedand for regulating the characteristics of the steam so that afterrelease it will be in a controlled state of wetness or vapor contentfavorable to deliver a uniformly effective deposit of 2 moisture uponthe material undergoing treatment and with substantial uniformity acrossthe material even though it may have considerable width. I

Another object of the invention is to provide compact steam conditioningand dischargemeans adapted to be disposed adjacent material to betreated for conditioning steam to a desired state of saturation or vaporcontent and substantial freedom from entrained droplets of water andthereafter releasing the steam under conditions causing an increase inits vapor phase content or wetness of such extent as to be favorable toimpart a uniformly effective deposit of moisture to the material beingtreated.

The manner in which these and other objects of the invention areattained will be evident from the following description taken inconjunction with .the accompanying drawings and the appended claims.

In the drawings- Fig. 1 is a diagrammatic side elevation showing oneform of apparatus embodying an application of the invention for settingmoisture-setting inks printed on a continuous web of paper material;

Fig. 2 is a side elevation showing in greater detail one of the steamconditioning and releasing units included in the apparatus of Fig. 1,some portions of the unit being shown broken away and some being showninsection for clarity of illustration;

Fig. 3 is a fragmentary plan view of one end portion of the unit of Fig.2; and I Fig. 4 is a vertical section taken on line 4-4 of Fig. 2.

The printing industry for some time has been familiar with thecomposition and use of so called moisture-setting inks which are printedon paper in any usual or convenient way and are then set to anon-smudging and non-offsetting condition by supplying to themoisture-sensitive ink on the paper sufficient water to causeprecipitation of the ink binder. Such inks generally contain anyappropriate or desired pigments associated with a water-precipitable inkbinder material .dissolved or dispersed in an organic solvent which issubstantially non-volatile at ordinary press room temperatures so thatthe ink will not set merely by evaporation or drying of the solvent inthe manner of more conventional types of inks. The organic solvent does,however, have hygroscopic characteristics such that it will take upmoisture from surrounding moist atmosphere. The binder and solvent areselected and correlated with respect to their solvent and solubilityproperties so that the binder will remain in solution in the organicsolvent alone but will be precipitated from a mixture of the solventwith the amount of water which it takes up from surrounding moistatmosphere when subjected to a setting treatment.

Moisture-setting inks having properties as above described may beobtained commercially from the General Printing Ink Corporation,Division of Sun Chemical Corporation, and the Hilton Davis Company andare designated Hydry inks. While various constituents may be used, it isunderstood that a typical formulation utilizes diethylene glycol as theprincipal hygroscopic solvent and contains a maleic acid type resineither alone or in admixture with zein as the water-precipitable binder,together with the usual appropriate and desired pigments. Such inks areprinted on paper by means of any appropriate type of printing pressequipment and the 'inks are then set to a non-smudging andnon-offsetting condition by supplying moisture thereto in such quantitythat the hygroscopic solvent of the ink will take up a sufficient amountof water-to render the binder insoluble in the mixture of solvent andwater and cause it to be precipitated with resultant setting of the inkto a firm condition.

In accordance with the present invention, the requisite moisture forsetting the ink on the paper is supplied in the form of pre-conditionedsteam released in the immediate vicinity of the paper after the ink hasbeen printed thereon. The state of the steam is carefully controlled andcorrelated with the hygroscopic powers of the ink solvent so that, whenit is released and reaches the immediate vicinity of the printedmaterial, the steam will be in a state of wetness comparable to densefog which has been found to be most favorable to transfer of moisture ina desired effective and uniform manner to inks of the characterdescribed. At the same time the state of the steam also is controlled soas to be substantially free of large droplets of water such as wouldtend to produce water spotting of the paper as well as non-uniformsetting of the ink. In addition to precipitating the ink binder andsetting the ink, the steam treatment serves a further desirable functionin the invention in that, through its heating effect, the steam servesto promote penetration of the ink into the paper and such penetration iseffected with increased uniformity as a result of the practicing of theinvention.

The present invention may with advantage utilize low pressure boilersteam which, as normally supplied in industry, is in a too wet conditionwith considerable entrained water and is therefore not initiallysuitable for use in applying moisture uniformly to the printed web,either from the standpoint of aifording a satisfactory agent forimparting the desired moisture to the hygroscopic solvent of the ink orfrom the standpoint of avoiding water spotting or other damage to orimpairment of the printing or of the paper itself. In accordance withthe invention, however, such initially unsuitable steam is freed ofentrained water and conditioned to such state that, upon release intocontact with the web it will be converted to that state of readilyabsorbable wetness correlated with the hygroscopicity characteristics ofthe solvent which has been found to be favorable to imparting thedesired amount of moisture to the ink and the paper substantiallywithout water spotting the paper.

In a preferred embodiment of the invention, this is accomplished bysupplying the too wet and initially unsuitable steam at superatmosphericpressure and then subjecting it to successive expansions with drying ordewatering accompanying at least one expansion after which the expandedsteam is released to the atmosphere in the vicinity of the printed weband is directed against the printed face of the web.

The conditions under which the steam free of entrained water is expandedand released and the space relationships between the steam releasing andconditioning unit and the printed web are so regulated and controlledthat the steam when released is substantially free from entrained waterand in such state of saturation or vapor content as to mix readily withthe hygroscopic solvent of the ink. The steam is preferably in the formof a finely dispersed fog produced partly by loss of heat energy inmechanical work performed in causing-it to scrub against the paper web,as well as by its admixture with the cooler atmosphere in the vicinityof the web and its contact with the printed web itself which ordinarilywill be at a lower temperature than the dew point of the steam andusually at room temperature or thereabout.

By controlling factors influencing the properties and characteristics ofthe released steam so that it is free of objectionable droplets ofentrained water and yet remains in such state of saturation, correlatedwith the hygroscopicity characteristics of the ink solvent, as .toreadily be absorbed by the hygroscopic solvent upon cooling in thevicinity of the web or directly upon the printed material itself andthus to effectively impart moisture to the solvent, it is possible toachieve satisfactory and uniform setting of moisture-setting inks whileminimizing difficulty with water spotting and similar damage to: orimpairment of the paper and .the ink. .1

A typical application of the invention inconnection with the printing ofmoisture-setting inks on a continuous web of paper material to be used,fore'xample, for bread wrapping and packaging purposes is illustrated inFig. 1. A web of paper [0, which may be an opaque bread wrapper stock,is supplied from a reel II to a printing press of the type employed formulti-color printing of bread wrappers. Thus, the web I 0 is passedabout a series of guide rolls 'I2 arranged as shown, then passedvertically upward between plate cylinders 13 and backing cylinders [4arranged in four successive pairs, as shown, for applying to the paperweb the desired printed impressions with inks of the moisture-settingtype as hereinabove described. The particular arrangement shown isdesigned for four-color work. The freshly printed web is then carriedover a lead roll 45, downward and forwardly to an idler roll l6,downward and rearwardly to loop about a guide roll l1, after which theweb is reeled up at l8. Rolls I5 and [6 may be ordinary smooth surfacedrolls since the unprinted side of the paper will be in contact withthem, but the roll H, which comes in contact with the printed side ofthe web, desirably should be of the' prick-roll type to further reducethe possibility of smearing the freshly printed web.

For setting the freshly printed ink on the paper web, one or more steamconditioning and releasing units, designated generally by the letter A,are mounted on suitable supporting means underheath the reach of the webbetween the rolls l6 and I1, as shown, the units being disposed in suchproximity to the web that steam emitted therefrom will impingeeffectively against the web. Pans 19 are provided about each of theunits A, the pans being mounted closely adjacent the path of the web, asshown, so as to substantially confine the steam after its release fromthe units.

One of the steam conditioning and releasing units A is shown in greaterdetail in Figs. 2, 3 and 4 of v the drawings which illustrate a specificembodiment of apparatus found satisfactory in commercial operations forsetting inks of the moisture-setting type printed on a traveling. web tobe used for bread wrapping purposes. Such specific embodiment ofthe unitA comprises an elongated heat exchanger or expansion element, means forcontrolling admission of steam thereto, and means for supporting saidelement in operative proximity to a traveling paper web .in a generallytransverse direction with respect to. the path of the web. Said heatexchanger includes an outer shell 30 or tube conveniently formed of 2/2" black iron pipe with an overall length of 80%;. One end of the pipeis closed by a plug 3| welded in plac while the other end is closed by areducing joint 32 threaded to the end of the shell 33 and having atubular extension or inlet 33 corresponding in size to a 1" pipe with anopening of 0.864 sq. in. cross-sectional area. The tubular inlet 33 isconnected by suitable piping to a source of steam, as boiler, not shown.A globe valve 34 or the like is provided-in the steam supply line nearthe unit for regulating the quantity and pressure of steam admittedthereto. A pressure gage 35 is tapped into the reducing joint 32 forindicating the pressure condition within the outer or first expansionchamber formed by the shell 30. For removing or draining water from thechamber C-l, a discharge pipe 36 may be tapped into the shell 30- at alowermost point near the end thereof removed from the steam inlet, thepipe 33 leading to a conventional trap 31.

A longitudinallyextending section of the outer shell30 about wide is cutout from a point 1 from the threaded end of the shell substantially tothe other end to provide a longitudinally extending opening through theshell wall. This opening is. closed, however, by a second tubular member38 forming an inner or second expansion chamber which is considerablysmaller than the outer shell or chamber 30 and is set within said outershell and welded to the margins of the aforesaid opening at 39 as shownmore clearly in Fig. 4. The second, or inner, tubular member 38 isformed of seamless steel tubing of 1%" inside diameter and 1%" outsidediameter, and is 74" long overall. Both ends of the tubular member 38-are closed by its steel disks or plugs 40 welded in place. As may beseen from Fig. 2, the inner tubular member extends from a point adjacentthe inlet 33 to the other end of the shell 30 andthrough the end disk 3|so as to project about 2" beyond the end of the outer shell 39 to permitconvenient connection of a discharge pipe 4| leading to a trap 42. forremoving or draining water from the chamber C-Z within the inner tubularmember 38. a

-For admitting'steam from the outer chamber C-i to the inner chamber0-2, a series or row of circular apertures 43 is provided in the wall ofthe tubular member 38. In the particular apparatus being described, theapertures 43 correspond in size to a No. 52 drill or 0.063 diameter andare 3'7 in number arranged in equally spaced relation, 2 apart, along asubstantially medial line extending longitudinally of the member 38.

These apertures 53 provide in the aggregate a cross-sectional area equalto 0.114 sq. in. for permitting steam flow from the outer chamber to theinner chamber.

For discharging steam from the inner chamber 0-2 to the atmospherecontiguous to the material being treated, a series of outlet or jetorifices 44 are provided through the exposed portion 45 of the wall ofthe inner tubular member 38. The orifices 44 are disposed along alongitudinal line extending medially between the margins of the exposedportion 45 of the inner tube 38, or, in other words, medially betweenthe margins of the longitudinal opening in the outer tube 30. In thespecific structure shown and described the orifices 44 should be 592 innumber and should correspond in size to a #52 drill, or 0.063 diameter,spaced apart, providing an aggregate outlet area equal to 1.835 sq. in.

As may be seen more clearly from Fig. 4, the structure describedprovides an outer or first condensing or expansion chamber C-l ofcrescentiform cross-sectional contour and an inner or second condensingor expansion chamber 0-2 of circular cross-sectional contour disposedwith a major portion of its wall area exposed to steam in the chamberC-l, the cusps of the crescentiform outer chamber extending about andembracing a major portion of the periphery of the inner chamber wall. Asmay be readily calculated, the cross-sectional area of the outer orinitial expansion chamber C-l is equal to 3.108 sq, in. and its volumeapproximately 240 cu. in. neglecting the slight volume in the shell ofthe reducing joint 32 and deducting the volume of the plug 3|. The inneror second chamber G4 has a cross-sectional area of 1.48 sq. in. and anoverall length of and, accordingly has a volume of approximately 118 cu.in. after correction for the volume of the thick end plugs. The volumesof the two chambers C-1 and 0-2 are therefore seen to be related in theapproximate ratio of 240 to 118 or approximately 2 to 1.

Steam supplied at the inlet 33 at superatmospheric pressure ismaintained under superatmospheric, even though lower, pressure in theunit and emerges from the outlets with velocity sufficient to bring thesteam into efiective moisture imparting contact with the printed web.

The two steam-releasing units A as employed in the illustrated apparatusare preferably disposedside-by-side transversely of the path of thetraveling web and in predetermined spaced parallel relationship theretoso that the released steam will impinge against the printed face or" theweb as a jet or steam of vapor with sufficient velocity to produce anadequate volume of absorbable vapor but not great enough to entrainwater droplets in the released jets. A spacing of about 1 /2 inchesbetween the outlet orifices 44 and the web has been found satisfactoryin the described installation although some variation in this spacing ispermissible. The important factor is to dispose the steam outlets closeenough to the web to insure the steam jets striking the printed materialwhile the steam is still traveling and in moisture imparting condition.The outlets 44 or some of them may be disposed at an angle with respectto the web so as to cause the emitted steam flowing in the direction ofthe advancing web to strike the web at an angle and thereby to produce asubstantial scrubbing efr fect. An angle of the order of 10-15 degreesbetween the direction of the steam jet and a perpendicular to the pathof the web or, in other words, an angle of about 75-80 degrees betweenthe jet direction and the path of the web itself, as shown in thedrawings, has been found satisfactory.

In operation, the web I0 may be, for example, a 25 pound opaque breadwrapper stock printed in multicolors with moisture-setting inks such asthe commercial inks hereinabove mentioned. The printed web may be causedto travel through the guide roll arrangement shown in Fig. 1, at a speedof about 300 to 400 feet per minute.

To set the ink on the paper steam is supplied from a boiler, not shown,to the expansion units A. Under usual conditions, steam obtained fromsuch source will arrive at the inlet 33 as a mixture of hot steam andunvaporized or free water which when released would be entrained in thejet in the form of droplets. Steam in this condition is therefore toowet and unsuitable initially for application directly to the printedpaper web. Inasmuch as the pressure required for the effective ultimateuse of the steam is relatively low, thatis of the order of a fraction ofa pound up to usually not more than about ten pounds 1). s. i., theinitial or feed in pressure need not be extreme. In a typical case,boiler steam at about pounds pressure reached the inlet 33 of each unitat about 11 pounds pressure, the loss being due presumably totransmission factors. According to the present invention, this too wetsteam, initially at about 11 pounds pressure, is now expanded from thesupply or inlet 33 into an expansion and heat exchanger zone, as chamber0-! where excess water, whether carried in with the initial steam orproduced by condensation, is collected and drained off through thedrainpipe 36 and trap 31 with resultant substantial drying of the steam.

The steam is again expanded as it passes through the apertures 43 intothe next zone, as the inner chamber 04 wherein, and as a result of suchexpansion, the steam is under lower pressure than in the chamber C-l.The dewatered steam in the chamber C-Z tends to receive heat fromportions of the walls forming said chamber 0-2 which are in a largemeasure surrounded by the warmer steam in the chamber C-l It iscontemplated that residual unevaporated water .if any in the steam inthe chamber C-2 tends to vaporize thereby further drying of the steam tothe extent that vaporizing of residual water takes place. Althoughlittle if any condensate collects in the chamber 0-2 after the unit hasoperated for a time, some condensate may form when the steam is firstadmitted and while the unit is reaching its normal operating temperaturecondition. To remove any such condensate, a drain pipe M is providedleading from the chamber 0-2 at a lowermost point in the protrudingsection of the inner tubular member 38 for conducting the condensate toa conventional trap 42.

' Thus, steam initially supplied in a too wet state and at a substantialsuperatmospheric pressure is conditioned by successive expansions withaccompanying removal of excess water to produce drier steam at a' lowerpressure but still above atmospheric pressure. The steam in thisconditioned state is then released to the atmosphere and to the moistureapplying zone through the outlet orifices 44 and expands to atmosphericpressure with accompanying cooling and admixture with the cooleratmosphere. After traveling through a short distance, of the order of 1%inches and at suflicient velocity to substantially saturate the air inthe moisture applying zone with vapor, the released steam comes intocontact with the cooler printed web, which usually will be at roomtemperature or thereabout. The steam undergoes still further cooling asa result of loss of heat energy in scrubbing against the web.

All of the foregoing contributing factors are controlled in practicingthe invention so as to bring the steam into contact with the movingprinted Web while it is in a condition of substantial freedom fromdroplets of water such as would tend to spot the paper but still in suchcondition of saturation that upon scrubbing against the cooler web, orupon being admixed with the cooler air immediately prior thereto, thesteam will condense suiiiciently to form fog or finely dispersed watervapor. In such condition, the de-watered steam has been found to impartmoisture to the hygroscopic solvent of the moisture-setting ink of thecharacter described in a uniform and generally satisfactory manner. Bycontrolling and regulating the several factors governing the state ofthe steam and correlatin these factors with the hygroscopic powers ofthe ink solvent in the manner indicated, it is possible to effectuniform and effective setting of the ink without impairing or damagingeither the paper or the printing thereon.

In utilizing various types of moisture-setting inks wherein thecoefiicient of hygoscopicity of the solvents may vary, the amount ofmoisture supplied to set the ink may be varied accordingly while stillretaining effective correlationship between the condition of the steamand the hygroscopic factor of the solvent. For example, the amount ofmoisture in the steam may be varied by suitable regulation of the valve34 to admit greater or lesser amounts of steam to the conditioning andreleasing unit. In practical operation with various inks, using theparticular installation described, especially satisfactory results havebeen obtained with steam pressures at the gage 35 as low as 3 pounds persquare inch and as high as 15 pounds per square inch.

While the process and apparatus herein described constitute a preferredembodiment of the invention, it is to be understood that the inventionis not limited to this precise form of process and apparatus, and thatchanges may be made therein without departing from the scope of theinvention which is defined in the appended claims.

What is claimed is:

1. In the printing of a web of paper or other material with ink of themoisture setting type wherein precipitation of the binder and setting ofthe ink is caused by taking up moisture from the surrounding moistatmosphere, the process of setting said ink which comprises the steps ofsupplying steam at a predetermined superatmospheric pressure, expandingsaid steam under confined conditions and removing water therefrom toeffect drying thereof, again expanding said dewatered steam to a lowersuperatmospheric pressure under confined conditions, maintaining saidsteam during said expansion in heat receiving association with asubstantially surrounding and higher temperature atmosphere forimparting heat to said steam during said second expansion to inhibitcondensation of water therefrom and to maintain said steam insubstantially dry state, releasing the expanded steam in the last saidcondition directly to the cooler atmosphere of a moisture applying zonewith accompanying further expansion under conditions imparting asubstantial velocity thereto, and causing said expanded steam to impingeupon said web to form adjacentsaid web a zone of substantially uniformlydistributed and finely dispersed moisture condensation free ofundesirab-ly large droplets of water.

2. In the printing of a Web of paper or other material with ink of themoisture setting type wherein precipitation of the binder and setting ofthe ink is caused by taking up moisture from the surrounding moistatmosphere, the process of setting said ink which comprises the steps ofsupplying steam at a predetermined superatmospheric pressure, expandingsaid steam under confined conditions and removing water therefrom toefiect drying thereof, again expanding said dewatered steam to a lowersuperatmospheric pressure under confined conditions, maintaining saidsteam during said second expansion in heat receiving association with asubstantially surrounding and higher temperature atmosphere of saidsteam from said first expansion for imparting heat to said steam duringsaid second expansion to inhibit condensation of water therefrom andmaintain moisture in said steam in a vaporized state, releasing theexpanded steam in the last said condition directly to the cooleratmosphere of a moisture applying zone with accompanying furtherexpansion under conditions imparting a substantial velocity thereto,and. causing said expanded steam to impinge upon said web to form insaid zone substantially uniformly distributed and finely dispersedmoisture condensation free of undesirably large droplets of water.

3. In the printing of a web of paper or other material with ink of themoisture setting type wherein precipitation of the binder and setting ofthe ink is caused by taking up moisture fro-m the surrounding moistatmosphere, the process of setting said ink which comprises the steps ofsupplying steam at a predetermined superatmospheric pressure, expandingsaid steam, under confined conditions to a lower superatmosphericpressure, surrounding said steam during said expansion with a highertemperature atmosphere of steam from said first expansion for impartingheat to said steam during said expansion to inhibit condensation ofwater therefrom and maintain moisture in said steam in a vaporizedstate, releasing the expanded steam in substantially dry conditiondirectly to the cooler atmosphere of a moisture applying zone withaccompanying further expansion under conditions imparting a substantialvelocity thereto, causing said web to travel in a path traversing saidzone, causing the released steam to impinge upon said Web at an anglewith the approaching web so as to eifect substantial scrubbing of thesteam against said web for imparting moisture thereto in uniformlydistributed fine suspension substantially free of undesirably largedroplets of water.

4. In the printing of a web of paper or other material with ink of themoisture setting type wherein precipitation of the binder and setting ofthe ink is caused by taking up moisture from the surrounding moistatmosphere, the process of rendering too wet and relatively highpressure steam into a substantially dry moisture conditioned and lowerpressure state for application to said web for setting said ink whichcomprise the steps of expanding said too wet steam under confinedconditions to lower the pressure thereof andmaintaining saidexpandedsteam in heat receiving associaton with a substantially surrounding andhigher temperature atmospherefor imparting heat to said expanded steamduring said expansion to inhibit condensation of water therefrom andcause the moisture in said expanded steam to assume a vaporized stateprior to releasing said moisture conditioned steam against said web.

5. Apparatus for setting moisture-setting ink imprinted upon a travelingweb of paper with, steam from a source of steam at superatmosphericpressure while the web istraveling in a predetermined path comprising afirst conditioning chamber communicating with said source of steam, asecond moisture conditioning chamber communicating with said firstchamber for expansion of steam therefrom into said second chamber, saidsecond chamber being so disposed with respect to said first chamber thatsubstantially all the Wall surface of said second chamber is in heatreceiving contact with steam in said first chamber for heating saidsecond chamber and the expanded steam therein for moisture conditioningand drying thereof, and outlet means from said second chamber fordischarging moisture-conditioned and substantially dry steam therefromas a jet of substantial velocity directed toward and impinging upon saidweb in controlled condition favoring transfer of moisture to said web inuniformly distributed and finely dispersed form.

6. Apparatus for setting moisture-setting ink imprinted upon a travelingweb of paper with steam from a source of steam at superatmosphericpressure while the web is traveling in a predetermined path comprisingan outer steam conditioning chamber communicating with said source ofsteam, an inner steam conditioning chamber communicating with said outerchamber for expansion of steam therefrom into said inner chamber, thewall of said outer chamber being interrupted to expose a limited portionof the wall of said inner chamber and said inner chamber being sodisposed within said outer chamber that substantially all the wallsurface of said inner chamber is in heat receiving contact with steam insaid outer chamber for heating said inner chamber and the expanded steamtherein for moisture conditioning and drying thereof, and outlet meansfrom said inner chamber at said exposed portion of the wall thereof fordischarging moisture-conditioned and substantially dry steam therefromas a jet of substantial velocity directed toward and impinged upon saidweb in controlled condition favoring transfer of moisture to said ink onsaid web in uniformly distributed and finely dispersed form.

'7. Apparatus for setting moisture-setting ink imprinted upon atraveling web of paper with steam from a source of steam atsuperatmospheric pressure while the web is traveling in a predeterminedpath comprising a first conditioning chamber and an inlet thereincommunicating with said source of steam, a second moisture conditioningchamber and an inlet therein communicating with said first chamber forexpansion of steam therefrom into said second chamber, said secondchamber being so disposed with respect to said first chamber thatsubstantially all the wall surface of said second chamber is in heatreceiving contact with steam in said first chamber for heating saidsecond chamber and the expanded steam therein for moisture conditioningand drying thereof, and outlet means from said second chamber fordischarging moisture-conditioned and substantially dry steam therefromas a jet of substantial velocity directed toward and impinging upon saidweb in controlled condition favoring transfer of moisture to said ink onsaid web in uniformly distributed and finely dispersed form, thecross-sectional areas of said inlets to said first and second chambersand said outlet means from said second chamber being of increasing sizeand so correlated as to provide for successive expansions of said steamas it passes into and through said chambers and is discharged into theatmosphere.

8. Apparatus for setting moisture-setting ink imprinted upon a travelingweb of paper with steam from a source of steam at superatmosphericpressure while the web is traveling in a predetermined path comprising afirst steam conditioning chamber communicating with said source of steamfor expansion thereof into said chamber to a reduced superatmosphericpressure, a second steam conditioning chamber communicating with saidfirst chamber for further expansion of said steam therefrom into saidsecond chamber, substantially the entire wall surface of said secondchamber being in heat receiving contact with a higher temperatureatmosphere outside said chamber for imparting heat into said chamber andto the steam expanding therein to inhibit condensation within saidchamber and maintain the moisture in said 12 chamber in vaporized state,and outlet means from said second chamber for dischargingmoisture-conditioned and substantially dry steam therefrom as a jet ofsubstantial velocity directed toward and impinging upon said web incontrolled condition favoring transfer of moisture to said ink on saidweb in uniformly distributed and finely dispersed form, said chambersbeing disposed in predetermined spaced relationship with said path.

CARL A. IRETON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

